Inflatable airbag devices, which are more commonly referred to in the art as Supplementary Restraint Systems (SRS), Air Cushion Restraint Systems (ACRS), or Supplemental Inflatable Restraint (SIR) Systems, are originally equipped in almost all present day automotive vehicles. Included as part of an overall occupant restraint system, airbag devices are generally located in the vehicle passenger compartment, and act as a selectively deployable cushion capable of attenuating occupant kinetic energy. Moreover, airbags are designed to minimize inadvertent movement of the driver and/or other occupants to help avoid involuntary contact with interior portions of the automobile.
Traditional airbag devices comprise an inflatable airbag module stored behind the vehicle instrument panel (e.g., for passenger-side airbags), mounted to the steering wheel (e.g., for driver-side airbags), or packaged under the trim lining along the vehicle roof rail (e.g., side curtain airbags). A plurality of sensors or similar devices is strategically located throughout the vehicle to detect the onset of a predetermined activation event (e.g., a sudden deceleration spike). The sensors responsively activate an inflation device, such as a solid propellant canister, that is internally located in the airbag module, to produce a flow of inflating gas into an inflatable flexible membrane (i.e., an airbag cushion), which is normally folded inside of the airbag module. This causes the airbag cushion to deploy within the vehicle passenger compartment.
Most driver-side air bag devices are housed inside of a module which is mechanically attached to the center hub of the vehicle steering wheel assembly, for example, by rivets or threaded fasteners. Modular airbag devices with snap-in steering wheel interfaces are also employed to reduce assembly costs. A functional and decorative cover encloses the air bag. The cover is normally manufactured with a tear seam which the air bag cushion ruptures during inflation to enable the air bag to deploy. The air bag module normally utilizes numerous fasteners and stampings to assemble the component parts together into the module, and to mount the module to the steering wheel assembly.